Abstract: A spread spectrum communication system for performing spread spectrum communication by superimposing a pseudo noise signal on a transmitted signal. The system comprises traffic detecting means for detecting the traffic of the transmitted signal, and means for changing the clock frequency of the pseudo noise signal in accordance with the output from the traffic detecting means. The system may alternatively comprise transmission quality determining means for determining the transmission quality of the received signal, and means for changing the clock frequency of the pseudo noise signal in accordance with the transmission quality determined by the transmission quality determining means. In operation, the system offers improved S/N ratios where traffic is high or transmission quality is low, saves power where traffic is low or transmission quality is high and ensures large margins of power control precision for mobile stations near the upper limit of the system's line capacity.

Abstract: A spread spectrum communication system for performing spread spectrum communication by superimposing a pseudo noise signal on a transmitted signal. The system comprises traffic detecting means for detecting the traffic of the transmitted signal, and means for changing the clock frequency of the pseudo noise signal in accordance with the output from the traffic detecting means. The system may alternatively comprise transmission quality determining means for determining the transmission quality of the received signal, and means for changing the clock frequency of the pseudo noise signal in accordance with the transmission quality determined by the transmission quality determining means. In operation, the system offers improved S/N ratios where traffic is high or transmission quality is low, saves power where traffic is low or transmission quality is high, and ensures large margins of power control precision for mobile stations near the upper limit of the system's line capacity.

Abstract: Digital signals of up to four different modes are produced for transmission over an unused television channel in an existing cable television transmission line. No more bandwidth is required than that normally required by a single existing television channel. The various modes of digital signals all include synchronizing signals and service bit signals which are used to address any of the numerous terminals at the receiving side to control access to the various modes of digital signals transmitted over the single channel. By controlling the transmission of the modes to have constant time intervals, which can be selected based upon different sampling times, high quality audio signals may be transmitted or/and data channels or monaural audio signals, all of which may be transmitted over the single cable television transmission line.

Abstract: A waveform shaping apparatus includes a shift register having a clock input terminal, data input terminals supplied with respective bits of a digital input signal and a plurality of data output terminals, and a plurality of coefficient multipliers connected to the respective data output terminals. A 2's-complement binary code offset within a predetermined range is used for representing the coefficient of each of the multipliers and such coefficient is controlled by manipulation of ON/OFF switches.